The product is a bio-pellet reactor NP-250 from the manufacturer Macro Aqua. Biopellets are a natural product designed for use in the aquarium. They are 100% biodegradable and decompose to carbon dioxide and water. Biopellets will destroy nitrates and phosphates, which are the main food products for algae. To remove them permanently and protect the aquarium from greening, you need special help. There are bacteria in the aquarium that feed on phosphates and nitrates, but to cope with their high values, they need carbon and energy. Biopellets provide them. In this way, bacteria absorb excess nutrients much faster. It is best to use biopellets in a reactor such as the NP-250 Biopellet Reactor with constant running water to supply the bacteria with the oxygen they need.